A diagram of a pathway of amino acid biosynthesis is shown .Enzymes are indicated by letters, and intermediates of the pathway indicated by numbers . Compound 5 most likely regulates which of the following labeled enzymes?

A B C D
1 - 2 - 3 - 4 - 5.

E F
6 - 7.

note: 2 way of this pathway folowing numbers :1-2-3-4-5. and 1-2-6-7.
Sorry hardly
to make arrow on this messages.